Area codes · +1
Area code 557
Area code 557 covers Missouri. We hold 839 allocated blocks for it across 7 rate centres, split 45% mobile, 20% landline and 35% VoIP.
The other area codes laid over 557
Area code 557 does not have None to itself. 1 other code — 314 — serves the same rate centres, laid over the same ground rather than dividing it. That is an overlay: a new code added when the old one ran out of numbers, covering the same streets. Two neighbours can hold different area codes, so the code says roughly when a number was issued rather than where it sits.
3145,722 blocks, 7 rate centres, mostly landline
Each holds its own blocks and its own carrier mix, so a 557 number and a 314 number from the same street can report different line types. Filtering None by area code needs all 2 of them.
557 is not confined to None itself: its blocks sit across 7 rate centres, named in the table below.
Missouri is split across 9 area codes — 573, 816, 314, 417, 636, 557 and others. By allocated blocks 557 is the 7th largest of them, holding 3% of the Missouri total.
Where 557 numbers are concentrated
NANPA truncates rate-centre names to ten characters and drops the spaces, which is why St Louis is shortened. Names are reproduced as recorded rather than expanded — the abbreviation is the key the block data is filed under.
| Rate centre | Blocks | Share of 557 |
|---|---|---|
| St Louis | 357 | 43% |
| Ladue | 180 | 21% |
| Kirkwood | 132 | 16% |
| Crevecoeur | 59 | 7% |
| Mehlville | 50 | 6% |
| Sappington | 48 | 6% |
| Oakville | 13 | 2% |
Carriers holding the most 557 blocks
AT&T Wireless275 blocks
Onvoy245 blocks
Teleport Communications America, Llc155 blocks
Verizon Wireless53 blocks
Onvoy Spectrum25 blocks
Boost Subscriberco L.L.C.17 blocks
The largest holder, AT&T Wireless, has 33% of the code.
These are original allocations. A number keeps its digits and its block when its subscriber moves network, so a ported 557 number still reports the carrier it started with. Closing that gap needs a live query against the routing database. How line type is derived.
Check a single 557 number, or run a whole list through the free cleaner — neither uploads anything.
Common questions
Where is area code 557?
Area code 557 covers Missouri. It is not the only code there: 314 is an overlay on the same rate centres, so a Missouri number can start with any of them.
Is a 557 number a mobile or a landline?
It can be either, and the digits do not say which. North American mobile and landline numbers share the same ranges, so the answer comes from the carrier holding the block. In 557 the split runs 45% mobile, 20% landline and 35% VoIP, so mobile is the most likely single answer.
Which carriers hold 557 numbers?
The largest holders are AT&T Wireless, Onvoy, Teleport Communications America, Llc. That is the carrier the block was allocated to, which is not necessarily the network a given number sits on today.
How many 557 numbers are there?
The code holds 839 allocated blocks in our copy of the numbering plan. A block is 1,000 or 10,000 consecutive numbers depending on how deeply it has been pooled, so 557 covers on the order of 839,000 possible numbers — most of which have never been issued to anyone.